Photochemical apparatus



W. O. SNELLING.

PHOTOCHEMICAL APPARATUS. AarLlcAlxoN FILED MAR. 6. 1917.

1,382,252. I Patented M521, 1921.

f QA/*m27 mwdw .wwmfm ATTORNY WALTER. lo.. sNnLLmG, or 'eLLENToWm PENNSYLVANIA. I

Pnorocnnmionr, nrrsna'rus.

Specification of Letters Patent. Patented June 21', 1921.

application `filed marcire, i917; v serial No. 152,588.

To all wlwm t ma@ concern I Beit known that I, WALTER 0. SNnLiiiNjG, a citizen of the United States, and a resident of Allentown, in the county of Lehigh and State of Pennsylvania., have invented a' new and useful Improvement in Photochemical Apparatus, of Whichtlie following is aspeci-u p cation. h

My invention relates to photocliemi'cal re'- actionsl involving lthe exposure vof mixtures Aof liquid, vaporous or, gaseous reagents to actinic rays for the purpose of inducing or facilitating their interaction, and one 0f my `objects is to provide a simple and commercially practicable process' of producing pho-.

- tochemical reactionproducts atta rapid rate lates tend to proceed with explosive violence and with a minimum expenditure of actinic energy. One ,specific application of this process is in the production of halogenated carbon compounds such as carbon tetrachlorid, chloroform, methylene chlorid and other compounds which are roduced by mixing gaseous or vapor0 ushy rocarbons with chlorin gas, bromin or, iodin vaporsandexposing-V the mixturesv to actinic` light.

Another object of inyfinventionv is to provideapparatus of inexpensive and conven- I ient construction for carrying outmy above and lconnected that'pthe mixture of reactive gases' or vapors is caused to cross and reindicated process. v'

The reactions to which my invention reand are therefore of little technical value unless means are provided lfor materially reducing the reaction velocity. In` my pending applicationsfor Letters Patent, Se'- vmi No. 776,834, sied Juiy 1,1913, serial No. 848,355, iiled July 1, 1914, and 'Serial N o. 132,869, filed November 22, 1916, I have described and claiinec'l'aV method of decel-l erating photochemical reactions by causing .mixtures of reactive gases or liquids to approach a source of actinic li ht by a path which is so related to-the lig t sourceV that the light Whichreachesthe entering reactive 'mixture has passed through'a considerable mass of partially combined reagents which serve to screen or filter out the'actinic rays' in proportion' to the thickness of the massof reacting gases. -The light is thus'pro- -gressive1y consumed and deprived lof l'its energy, while Vthe reactive mixture, movingA 4in countercurrent relation 'to fthe light rays,

` meets with light ofgreater and greater in- Y tensity as it advances, andas the tendency 'tribution of lightl In =my earlierapplications' which I have mentioned above, I have described my coun- .tereurrent principle of photochemicalftreat- .erable 'number o f' times.

Ais a modification-of these processes and is co- 'toivard'high reaction velocity decreases by reason of the progressive completion of the 'reaction'.v My present invention is concerned with certain developments 0f this general countercurrent-7 principle of photocliemical treatment,l and is illustrated in the ,accompanying drawing, in which:

igure l is a central vertical sectional..

other modiiiedjorm of device, provided with f means for diluti the incoming reaction mixture with partial or complete reaction products before bein exposed t the light, and 'F 1g. 4 is a simi ar view of a further modication of `my device in v`which an opaque inner dome is rovided for cooling the reacting gasesand fiir regulating the dismei'it with specific referenceto the use of Aa series of reaction chambers so constructed cross'vtlie patli'of the li ht ra s a considy y t presen process vcharacterized by the use of a single reaction vessel vonly and by certain methods and means wherein Ifmake use vof the countercurrent principle Without the use of aV pluralityof interconnectedreaction vessels.

In all ofthe several forms `of apparatus which are .shown herein, a mixture of photochemically Vreactive iiuids is caused to enter a transparent reaction dome at a point re mote fromasource of light which Ais preferably disposed outside of and adjacent to thedonie. An outlet foisgaseous or vaporous -reaction products is provided at the side of action mixture, at its entrance into the dome, is separated from the lightsouie by a 'thick inass of gases and vapors which have par tially or entirely reacted with each other. This interposed blanket of reacting gases and vapors serves to consume a large part i 'the dome nearest to the -light source, the resiIlt of this arrangement being thattlie reof the-chemically'active rays' 'from l.the light source, and therefore the gas mixture, `when it first enters the reaction chamber, 1s eX- posed onlyto relatively feeble rays which 'are not sufficiently active to bring about a degree of reaction which will raise the temy perature ofthe entering gases to the ignition Y point. Asthe gas vmixture advances towardthe outlet of the dome, it is met with `light' of'- rogressively increasing strength, in accor ance with the countercurrent principle which is outlined above anclis described and p 'claimed 1n my earlier applications.

According to a further.development `of m invention, Winch. is incorporated 1n certaln ofthe forms of devices illustrated here. in, I provide means for permitting the mixture ofV gases'or vapors which enters the- 4 'I reaction .chamber to partially diffuse, bei forebeingexposed to the rays from the light Source, with thel more or less completely combined gases or vapors which are already inthe chamber;l Several methods "for permitting such initial diffusion Vof the entering gases are illustratedin Figs. Q, 3

' and 4 of the drawing andv willbe more fully described below.

Referring now vto thegures of the drawing, the apparatus shown in F ig. 1 consists of a shallowl pan or trayl upon'which rests a. transparent dome 2 and adjacent to whichV is disposed a source of actinic light represented by a mercury vapor -lamp 3- The Vpan 1V maysuitably be, composed Vof lead.'

stoneware or some other material. which. is not attacked by the reagents' present, and is provided with a 'gas inletpipe 41, `a ga's outlet pipe 5 and a'fluid outlet pipe G. all of these pipes extending through the bottom of the `pan and' being sealed therein. The inlet pipe 4; and the outlet pipe 5 both extend into the interior of the dome 2 through j a 'liquid seal 7 which. serves to excludelthe outside'air from the interior of the dome and which mayv suitably consist of liquid reaction products formed Within the do1ne.

As shown, the outlet pipe o is materially longer. than the inlet pipe et and may extend. nearly to the top ofthe dome 2.

It Will` be observed that the light source 3 is disposed at the side of the dome nearest to the outlet pipe 5 and farthest frbm -the inlet pipe 4. By reasonl of this arrangement, the mixture of reactive gases or vapors introduced into the dome 2 throughthe pipe 4. moves toward the light source 3 in its passage to the outlet pipe 5, with the result that each portion of the gas mixture is irst subjected to light which is dim at first on account' of the absorptive effect of the gas blanket between the inlet and outlet pipes and which gradually increases as the lgases approach the outlet. The gases vcomposing the reaction mixture therefore re act Aprogressively and quietly. lf desired,

jets ofrair or water may be' directed downwardly upon the dome 2 in order to control the temperature of' the-reacting gases Vand insure that the gases shall'not be heated to the ignition point.

The form of device'shownin Fig. -2 is similar in many respects to that shownin Fig. 1, and the corresponding parts are similarly designated. In this device, however, the outlet pipe 5 is of about the same length as the inlet pipe 4 and is surrounded by atube 8 of somewhat larger diameter rthan the pipe 5, whichv is setfover theend of the pipe 5 in telescoped relation thereto and produces the same effect as the longer pipe 5 shown in Fig. 1.

The light source shown inV Fig. 2 consists of 'a'. mercury vapor. lamp 9 or other elongated luminous body which is disposed horizotally near the edge of the pan 1. An adjustable screen 10 is adaptedl to beinterposed between. the lamp and the dome.

vthrough the reaction mixture' between the inlet and the outlet. -By vertically adjustingV the screen 10, the incoming'gases may be caused to diffuse .to a greater or less ldef gree. i i

Fig. 3 shows a structure which is essentially similar to that shownin Fig. 1, with \vith,'a series of draft openings 14 somewhat below the upperend of `the pipe 4. The gases entering `the dome through the pipe 4 aspirate a portion of the gaseous con tents ofthe dome through the openings 14- and mix with such gases in the upper part of the sleeve 13 before being subjected to the direct rays from the lamp 3.

F igzd shows an arrangement which comprises an annular pan 15 upon which is supported an inner dome 16preferably of meta-l, and an outer 4dome 2, of glass or other transparent material, the remaining features of' this form of device being similar to those shown in Fig. 1. The metal dome 16 serves to permit diffusion of the incoming gas mixture with the partially combined gaseous matter between dome 2 and dome 16 before being subjected to the direct rays of light from the lamp In this form of device, the temperature between dome 2 and dome l.at-he addition of a sleeve or chimney 13 of.` glass, porcelain or the like, which surrounds the inlet pipe 4. The sleeve 13 is 4provided' 16 may he effectively controlled by blowing hot or cold air into the interior of the inner dome 16.

The apparatus which I have shoivn and described ot particular advantage in preparing chlorinated hydro :arbons from mixtures of chlorin and natural gas. Using a glass dome about 1S inches in diameter and exposed to the full rays of the sun, I am able to deliver mixed chlorin and natural gas to the dome at a rate in excess ot l cubic foot per minute With complete and quiet reaction to produce large quantities of chloroform and other chlorin compoundsr TheV dimensions of the domesto `be used in carrying out my invention should be selected in accordance with the actinic strength of the light to be employed., a' diameter ot' G inches being the practical minimum diameter which I have found to be successful. Better results are obtained with domes from l foot to 18 inches in diameter.

The structures which I have shown and described may be associated with one another and with other apparatus in various ways and may be modified in many particulars as will be apparent to those skilled in the construction and operation ot' chemical apparatus. It is to be understood that the structural details herein shown are intended tobe illustrative only and not as imposing'restrictions upon my invention, which is to be limited only by the scope of lthe appended claims.

I claim as my invention:

l. Photochemica-l apparatus comprising a shallow pan or tray, a transparent dome adapted to rest thereon, fluid inlet and outlet conduits extending through the bottom of the said pan and adapted to enter the said dome, and an extension for one ot' the said conduits comprising a tube of larger diameter than the said conduit and in telescoped relation thereto. y

2. Photochemical apparatus comprising a shallow pan 0r tray, a transparent dome adapted to rest thereon, fluid inlet and outlet conduits extending through the bottom ot' the said pan and adapted to enter the said dome, the said outlet" conduit being materiallv longer than the said inlet conduit, and' a light source adapted to project actinic rays into the interior of the said dome and disposed nearer to the said outlet conduit than to the said inlet conduit.

2%. Photochelnical apparatus comprising a transparent reaction vessel of relatively large diameter as compared with its length, a light source'adapted to project actinic rays into the said vessel, fluid inlet and outlet conduits extending into the said vessel, and means for causing the fluid issuing from the said inlet conduit to partially di'use with the contents of the said vesselV before being exposed to rays from the said light source.

el. Photochein'ical apparatus comprising a transparent reaction vessel, fluid inlet and outlet conduits extending into the said vessel, and a'sleeve surrounding the said inlet conduit. within the said vessel and provided With a plurality of openings disposed adjacent to the end of the lsaid inlet conduit.

5. Ihotochemical apparatus comprising a transparent reaction vessel, fluid inlet and outlet conduits extending into the said vessel, the said outlet conduit being materially longer than they said inlet conduit, a light source disposed adjacent to the said vessel and nearer t-o the said outlet conduit than to the said inlet conduitpand a sleeve surrounding the said inlet conduit within tliae said vessel and provided With a plurality of openings disposed adjacent to the end of the said inlet conduit.

6. Photochemical apparatus comprising a transparent reaction vessel of relatively large diameter as compared with its length, iiuid inlet and outlet conduits extending into the said vessel. a light source disposed adjacent to the said vessel, and an opaque member disposed ivithin the sa'id vessel and adapted to .permit the iiuid issuing from the said inlet conduit to partially diffuse with the contents of the said vessel before being exposed to rays from the said light source.

In testimony whereof, I have hereunto subscribed my name this 27th day of February, 1917.

WALTER o. SNELLING. 

